Layouts of multiple transformers and multiple rectifiers of interleaving converter

ABSTRACT

The present invention relates to multi-phase parallel-interleaved converter circuits with each phase having two or more transformers and two or more rectifiers electrically coupled to the two or more transformers, and layouts of the transformers and the rectifiers of the multi-phase parallel-interleaved converter circuits. In the layouts, the multiple transformers and the multiple rectifiers of the multi-phase converters are interleavingly arranged to be symmetrical to common output polarized capacitor(s) so as to ensure the rectifier outputs of each phase relative to the common output polarized capacitors is symmetrical, thereby reducing the output ripples of the current of the output capacitors.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application is a continuation-in-part application of a co-pendingU.S. patent application Ser. No. 13/090,925, filed on Apr. 20, 2011,entitled “PARALLEL-CONNECTED RESONANT CONVERTER CIRCUIT AND CONTROLLINGMETHOD THEREOF”, by Haoyi Ye et al., which itself is a continuationapplication of U.S. patent application Ser. No. 12/394,571, Feb. 27,2009, entitled “PARALLEL-CONNECTED RESONANT CONVERTER CIRCUIT ANDCONTROLLING METHOD THEREOF”, by Haoyi Ye et al., which status isabandoned and which itself claims priority to and the benefit of,pursuant to 35 U.S.C. §119(a), Taiwan patent application No. 097109222,filed on Mar. 14, 2008, entitled “PARALLEL-CONNECTED RESONANT CONVERTERCIRCUIT AND CONTROLLING METHOD THEREOF”, by Haoyi Ye et al., all of thecontents of which are incorporated herein by reference in theirentireties.

This application also claims priority to and the benefit of, pursuant to35 U.S.C. §119(a), Chinese patent application No. 201210068354.0, filedMar. 15, 2012, entitled “LAYOUTS OF MULTIPLE TRANSFORMERS AND MULTIPLERECTIFIERS OF INTERLEAVING CONVERTER”, by Chao Yan et al., the contentof which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention generally relates to interleaving convertercircuits having multiple transformers and multiple rectifiers, and moreparticularly, to a resonant converter, and layouts of the multipletransformers and the multiple rectifiers of the interleaving LLC-SRCcircuits.

BACKGROUND OF THE INVENTION

An LLC series-resonant converter (LLC-SRC) has found widespreadapplications in power supply devices, because of its advantages overother types of converters. For example, its design is relatively simple,and can achieve the zero voltage switching (ZVS) operation of theprimary MOS (metal-oxide semiconductor) and the zero current switching(ZCS) operation of the secondary MOS in a full load range, therebyenhancing the system efficiency.

However, the output current of the LLC-SRC has a “half-chord” waveform.Additionally, when the switching frequency is lower than the resonantfrequency, the current of the secondary MOS is un-continued and itspeaks are relatively high, which increase not only thepredefined/specification values of component currents, but also theconduction losses of the converter.

The conventional LLC-SRC has drawbacks of which the output current haslarge ripples. In order to meet relatively same output voltage ripplesof a conventional PWM converter and requirements of the current ripplesof the capacitor, the outputs need to be parallel-coupled to a number ofcapacitors. To apply the LLC-SRC in strong current situations, it isnecessary to adapt an interleaving mode, that is, two or N LLC-SRCs areparallel-connected/interleaved. Using a control circuit to make theswitches of each LLC-SRC driven with a 90° or 180°/N shift mayeffectively reduce the output current ripples and increase the frequencyof the output current ripples, thereby reducing the number of the outputcapacitors, lowering the specifications of the power switching elements,so as to achieve the goal of reducing costs and increasing the outputpower and the power density while still having the advantages of theLLC-SRC ZVS and ZCS.

The parallel-interleaved LLC-SRC is applicable to power supplies of highpower and high current. The parallel-interleaved LLC-SRC mainly refersto a converter in which the outputs of two or more LLC-SRCs areparallel-connected and coupled to a common output filter capacitor. Whentwo LLC-SRCs are interleaved, there are two types of input connections:one is that the inputs are parallel-connected, which is adapted for thelow input voltages and used only for power amplification. The other isthat the inputs are series-connected, where a three-phase PFC isgenerally coupled prior to the inputs. Accordingly, the use of switcheswith lower voltage stress meets the requirements of high input voltages.In the two-phase interleaved LLC-SRC, the distribution of the rectifieroutputs at the secondary side is symmetrical relative to the commonoutput capacitor, whereby the amplitudes of the output currents of therectifiers in the two phases are equal, while and phases are shifted at90°. After the output currents are superpositioned, an output current ofthe output capacitor with small ripples can be achieved.

However, in practice, the length difference of the conductive wirestransmitting the rectifier outputs of the secondary sides of thetwo-phase interleaved LLC-SRC to the common output capacitor may resultin different parasitic resistances and parasitic inductances therein,thereby inevitably causing the asymmetry of the output currents.Consequently, the amplitude and phase shifts are generated in thetwo-phase rectifier output currents, which result in the increase of theripple current of the output capacitor, and deteriorating theparallel-interleaved effect.

In the low-voltage and strong-current applications, due to productspecifications, each parallel-interleaved LLC-SRC may have two or moretransformers. Considering the limitation of the current stress of therectifier MOS and the cost, each LLC-SRC may have two or morecorresponding rectifiers. If the layouts of the transformers andrectifiers are not appropriated, the interleaving effect will be greatlyreduced.

Therefore, a heretofore unaddressed need exists in the art to addressthe aforementioned deficiencies and inadequacies.

SUMMARY OF THE INVENTION

The present invention, in one aspect, relates to a converter circuit. Inone embodiment, the converter circuit has a first output and a secondoutput, and comprises a first converter and a second converter.

Each converter includes a switch network circuit; a first transformerand a second transformer, each transformer having a primary winding andat least one secondary winding, wherein the switch network circuit andthe primary windings of the first and second transformers areelectrically connected to each other; and a first rectifier and a secondrectifier electrically coupled to the secondary windings of the firsttransformer and the second transformer, respectively, each rectifierhaving a first output and a second output.

The first and second outputs of the first rectifiers of the first andsecond converters are electrically parallel-connected to a first outputcapacitor that is electrically connected between the first and secondoutputs of the converter circuit. The first and second outputs of thesecond rectifiers of the first and second converters are electricallyparallel-connected to a second output capacitor that is electricallyconnected between the first and second outputs of the converter circuit.

In one embodiment, each converter has a first input and a second input.The second input of the first converter is electrically series-connectedto the first input of the second converter. The first input of the firstconverter and the second input of the second converter are electricallycoupled to a voltage source for receiving an input voltage.

In one embodiment, each resonant converter further comprises a switchnetwork circuit, electrically coupled between the first and secondinputs and the resonant tank. In one embodiment, the switch networkcircuit of each resonant converter comprises a half-bridge circuit or afull-bridge circuit.

In one embodiment, each of the first and second output capacitorscomprises one or more high frequency filtering capacitors.

In one embodiment, each of the first and second rectifiers of eachresonant converter comprises a half-bridge circuit or a full-bridgecircuit.

In another aspect, the present invention relates to a layout of theresonant converter circuit as disclosed above.

In one embodiment, the layout includes a main board, a first sub-boardand a second sub-board spaced-apart and vertically attached to the mainboard along a predetermined direction. The first rectifiers of the firstand second resonant converters and the first output capacitor arespaced-apart disposed on one side of the first sub-board such that thefirst output capacitor is placed between the first rectifiers of thefirst and second resonant converters, and the first transformers of thefirst and second resonant converters are mounted on the other side ofthe first sub-board, spatially aligned with and electrically connectedto the first rectifiers of the first and second resonant converters,respectively. The second rectifiers of the first and second resonantconverters and the second output capacitor are spaced-apart disposed onone side of the second sub-board such that the second output capacitoris placed between the second rectifiers of the first and second resonantconverters, and the second transformers of the first and second resonantconverters are mounted on the other side of the second sub-board,spatially aligned with and electrically connected to the secondrectifiers of the first and second resonant converters, respectively.

In one embodiment, the first rectifiers of the first and second resonantconverters are placed symmetrically on two sides of the first outputcapacitor, and wherein the second rectifiers of the first and secondresonant converters are placed symmetrically on two sides of the secondoutput capacitor.

In one embodiment, the first transformers of the first and secondresonant converters are mounted on the other side of the first sub-boardby fixing pins of the secondary windings of the first transformers ofthe first and second resonant converters symmetrically on the firstsub-board. The second transformers of the first and second resonantconverters are mounted on the other side of the second sub-board bysymmetrically fixing pins of the secondary windings of the secondtransformers of the first and second resonant converters symmetricallyon the second sub-board.

In one embodiment, each sub-board has a positive output port and anegative output port electrically parallel-connected to a respective oneof the first and second output capacitors. The positive and negativeoutput ports of the first sub-board are electrically parallel-connectedto the positive and negative output ports of the second sub-board,respectively, which are electrically parallel-connected to the first andsecond outputs of the resonant converter circuit.

The layout may further comprises one or more polarized capacitorsdisposed on the main board, and wherein the one or more polarizedcapacitors are electrically parallel-connected to the first and secondoutputs of the resonant converter circuit.

In yet another aspect, the present invention relates to a layout of theresonant converter circuit as disclosed above. In one embodiment, thelayout includes a main board, and a sub-board vertically attached to themain board. The first rectifier of the first resonant converter, thefirst output capacitor, the first rectifier of the second resonantconverter, the second rectifier of the first resonant converter, thesecond output capacitor and the second rectifier of the second resonantconverter are spaced-apart and orderly disposed on one side of thesub-board along a predetermined direction such that the first outputcapacitor is placed between the first rectifier of the first resonantconverter and the first rectifier of the second resonant converter, andthe second output capacitor is placed between the second rectifier ofthe first resonant converter and the second rectifier of the secondresonant converter. The first transformer of the first resonantconverter, the first transformer of the second resonant converter, thesecond transformer of the first resonant converter and the secondtransformer of the second resonant converter are orderly mounted on theother side of the sub-board, spatially aligned with and electricallyconnected to the first rectifier of the first resonant converter, thefirst rectifier of the second resonant converter, the second rectifierof the first resonant converter and the second rectifier of the secondresonant converter, respectively.

In one embodiment, the first transformer of the first resonantconverter, the first transformer of the second resonant converter, thesecond transformer of the first resonant converter and the secondtransformer of the second resonant converter are orderly mounted on theother side of the first sub-board by fixing pins of the secondarywindings of the corresponding transformers on the sub-board.

In one embodiment, the sub-board has a first positive output port and afirst negative output port electrically parallel-connected to the firstoutput capacitor, and a second positive output port and a secondnegative output port electrically parallel-connected to the secondoutput capacitor. The first positive output port and the first negativeoutput port electrically parallel-connected to the second positiveoutput port and the second negative output port, which are electricallyparallel-connected to the first and second outputs of the resonantconverter circuit.

In one embodiment, the layout may also have one or more polarizedcapacitors disposed on the main board, and wherein the one or morepolarized capacitors are electrically parallel-connected to the firstand second outputs of the resonant converter circuit.

In a further aspect, the present invention relates to a resonantconverter circuit. In one embodiment, the resonant converter circuit hasa first output and a second output, and includes M resonant converters,{G_(m)}, m=1, 2, 3, . . . , M, M being an integer greater than one. Eachresonant converter G_(m) includes an resonant tank; N transformers{T_(m,n)}, and N rectifiers, {R_(m,n)}, n=1, 2, 3, . . . N, N being aninteger greater than one. Each transformer T_(m,n) has a primary windingand at least one secondary winding. The resonant tank and the primarywindings of the N transformers are electrically connected to each otherin series. Each rectifier R_(m,n) having a first output and a secondoutput, and electrically coupled to the at least one secondary windingof a respective transformer T_(m,n).

In one embodiment, the multiple transformers {T_(m,n)} and the multiplerectifiers {R_(m,n)} of the M resonant converters {G_(m)} are arrangedin N groups such that each group includes the n-th transformers T_(1,n),T_(2,n), T_(3,n), . . . T_(M,n) and the n-th rectifiers R_(1,n),R_(2,n), R_(3,n), . . . R_(M,n) of the M resonant converters {G_(m)}.For each group, the first and second outputs of the n-th rectifiersR_(1,n), R_(2,n), R_(3,n), . . . R_(M,n) of the M resonant converters{G_(m)} are electrically parallel-connected to a n-th output capacitor,C_(Fn), which is electrically connected between the first and secondoutputs of the resonant converter circuit.

In one embodiment, each resonant converter G_(m) has a first input and asecond input, wherein the second input of any one but the last resonantconverter G_(m) is electrically series-connected to the first input ofits immediate next resonant converter G_(m+1), and wherein the firstinput of the first resonant converter G₁ and the second input of thelast resonant converter G_(M) are electrically coupled to a voltagesource for receiving an input voltage.

In one embodiment, each resonant converter G_(m) further comprises aswitch network circuit, NC_(m), electrically coupled between the firstand second inputs and the resonant tank. In one embodiment, the switchnetwork circuit NC_(m) of each resonant converter G_(m) comprises ahalf-bridge circuit or a full-bridge circuit.

In one embodiment, each output capacitor CF_(n) comprises one or morehigh frequency filtering capacitors.

In one embodiment, each rectifier R_(m,n) of each resonant converterG_(m) comprises a half-bridge circuit or a full-bridge circuit.

In yet a further aspect, the present invention relates to a layout ofthe resonant converter circuit as disclosed above. In one embodiment,the layout includes a main board, and N sub-boards spaced-apart andvertically attached to the main board along a predetermined direction,where for each group, the n-th rectifiers R_(1,n), R_(2,n), R_(3,n), . .. R_(M,n) of the M resonant converters {G_(m)} and the n-th outputcapacitor C_(Fn) are spaced-apart disposed on one side of the n-thsub-board, and the n-th transformers T_(1,n), T_(2,n), T_(3,n), . . .T_(M,n) of the M resonant converters {G_(m)} are mounted on the otherside of the n-th sub-board, spatially aligned with and electricallyconnected to the n-th rectifiers R_(1,n), R_(2,n), R_(3,n), . . .R_(M,n) of the M resonant converters {G_(m)}, respectively.

In one embodiment, the n-th rectifiers R_(1,n), R_(2,n), R_(3,n), . . .R_(M,n) of the M resonant converters {G_(m)} are placed symmetrically ontwo sides of the n-th output capacitor on the n-th sub-board.

In one embodiment, the n-th transformers T_(1,n), T_(2,n), T_(3,n), . .. T_(M,n) of the M resonant converters {G_(m)} are mounted on the otherside of the first sub-board by fixing pins of the secondary windings ofeach of the n-th transformers T_(1,n), T_(2,n), T_(3,n), . . . T_(M,n)of the M resonant converters {G_(m)} symmetrically on the n-thsub-board.

In one embodiment, the n-th sub-board has a positive output port and anegative output port electrically parallel-connected to the respectiven-th output capacitor. The positive and negative output ports of the Nsub-boards are electrically parallel-connected to the first and secondoutputs of the resonant converter circuit, respectively.

The layout further has one or more polarized capacitors disposed on themain board, and wherein the one or more polarized capacitors areelectrically parallel-connected to the first and second outputs of theresonant converter circuit.

In one aspect, the present invention relates to a layout of the resonantconverter circuit as disclosed above. In one embodiment, the layoutincludes a main board, and a sub-board vertically attached to the mainboard, where for each group, the n-th rectifiers R_(1,n), R_(2,n),R_(3,n), . . . R_(M,n) of the M resonant converters {G_(m)} and the n-thoutput capacitor C_(Fn) are spaced-apart and orderly disposed on oneside of the sub-board along a predetermined direction, and the n-thtransformers T_(1,n), T_(2,n), T_(3,n), . . . T_(M,n) of the M resonantconverters {G_(m)} are mounted on the other side of the sub-board alongthe predetermined direction, spatially aligned with and electricallyconnected to the n-th rectifiers R_(1,n), R_(2,n), R_(3,n), . . .R_(M,n) of the M resonant converters {G_(m)}, respectively, so as todefine a respective sub-layout. Each sub-layout is arranged along thepredetermined direction.

In one embodiment, the n-th rectifiers R_(1,n), R_(2,n), R_(3,n), . . .R_(M,n) of the M resonant converters {G_(m)} are placed symmetrically ontwo sides of the n-th output capacitor on the sub-board.

In one embodiment, the n-th transformers T_(1,n), T_(2,n), T_(3,n), . .. T_(M,n) of the M resonant converters {G_(m)} are mounted on the otherside of the first sub-board by fixing pins of the secondary windings ofeach of the n-th transformers T_(1,n), T_(2,n), T_(3,n), . . . T_(M,n)of the M resonant converters {G_(m)} symmetrically on the sub-board.

In one embodiment, the sub-board has M pairs of positive and negativeoutput ports. Each pair of the positive and negative output portselectrically parallel-connected to the respective output capacitor. TheM pairs of positive and negative output ports are electricallyparallel-connected to the first and second outputs of the resonantconverter circuit, respectively.

In one embodiment, the layout further has one or more polarizedcapacitors disposed on the main board, and wherein the one or morepolarized capacitors are electrically parallel-connected to the firstand second outputs of the resonant converter circuit.

These and other aspects of the present invention will become apparentfrom the following description of the preferred embodiment taken inconjunction with the following drawings, although variations andmodifications therein may be effected without departing from the spiritand scope of the novel concepts of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate one or more embodiments of theinvention and together with the written description, serve to explainthe principles of the invention. Wherever possible, the same referencenumbers are used throughout the drawings to refer to the same or likeelements of an embodiment, and wherein:

FIG. 1 shows schematically a diagram of a resonant converter circuitaccording to one embodiment of the present invention;

FIG. 2 shows schematically a diagram of a single-phase LLS-SRC utilizedin the resonant converter circuit shown in FIG. 1.

FIG. 3 shows schematically a layout of the resonant converter circuitshown in FIG. 1 according to one embodiment of the present invention;

FIG. 4 shows schematically a layout of the resonant converter circuitshown in FIG. 1 according to another embodiment of the presentinvention;

FIG. 5 shows schematically a diagram of a resonant converter circuitaccording to one embodiment of the present invention;

FIG. 6 shows schematically a diagram of a single-phase LLS-SRC utilizedin the resonant converter circuit shown in FIG. 5; and

FIG. 7 shows schematically a diagram of a resonant converter circuitaccording to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described more fully hereinafter withreference to the accompanying drawings, in which exemplary embodimentsof the invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art. Likereference numerals refer to like elements throughout.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” or “includes” and/or “including” or “has” and/or“having” when used herein, specify the presence of stated features,regions, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and thepresent disclosure, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

As used herein, “around”, “about” or “approximately” shall generallymean within 20 percent, preferably within 10 percent, and morepreferably within 5 percent of a given value or range. Numericalquantities given herein are approximate, meaning that the term “around”,“about” or “approximately” can be inferred if not expressly stated.

The description will be made as to the embodiments of the presentinvention in conjunction with the accompanying drawings in FIGS. 1-7. Inaccordance with the purposes of this invention, as embodied and broadlydescribed herein, this invention, in one aspect, relates to interleavingconverter circuits having multiple transformers and multiple rectifiers,and layouts of the multiple transformers and the multiple rectifiers ofthe interleaving converter circuits.

Referring to FIGS. 1 and 2, a resonant converter circuit 100 is shownaccording to one embodiment of the present invention. The resonantconverter circuit 100 has a first input 101, a second input 102, a firstoutput 103, a second output 104, a first resonant converter G₁ and asecond resonant converter G₂.

In one embodiment, the first and second resonant converters G₁ and G₂are structurally the same. As shown in FIG. 2, the first resonantconverter G₁ includes a switch network circuit SNC₁, an resonant tankLLC₁ electrically coupled to switch network circuit SNC₁, a firsttransformer T_(1,1) and a second transformer T_(1,2) electricallycoupled to the resonant tank LLC₁, a first rectifier R_(1,1) and asecond rectifier R_(1,2) electrically coupled to the first transformerT_(1,1) and the second transformer T_(1,2), respectively.

Specifically, each transformer T_(1,1)/T_(1,2) has a primary winding andtwo secondary windings. The resonant tank LLC₁ and the primary windingsof the first and second transformers T_(1,1) and T_(1,2) areelectrically connected to each other in series. The first and secondrectifiers R_(1,1) and R_(1,2) are electrically coupled to the secondarywindings of the first and second transformers T_(1,1) and T_(1,2),respectively.

Each rectifier R_(1,1)/R_(1,2) has a first output 111/113 and a secondoutput 112/114. As shown in FIG. 1, the first outputs 111 and 121 andthe second outputs 112 and 122 of the first rectifiers R_(1,1) andR_(2,1) of the first and second resonant converters G₁ and G₂ areelectrically parallel-connected to a first output capacitor C_(F1) thatis, in turn, electrically connected between the first and second outputs103 and 104 of the resonant converter circuit 100. The first outputs 113and 123 and the second outputs 114 and 124 of the second rectifiersR_(1,2) and R_(2,2) of the first and second resonant converters G₁ andG₂ are electrically parallel-connected to a second output capacitorC_(F2) that is, in turn, electrically connected between the first andsecond outputs 103 and 104 of the resonant converter circuit 100.

Additionally, each resonant converter G₁/G₂ has a first input 115/125and a second input 116/126. The second input 116 of the first resonantconverter G₁ is electrically series-connected to the first input 125 ofthe second resonant converter G₂. The first input 115 of the firstresonant converter G₁ and the second input 126 of the second resonantconverter G₂ are electrically coupled to the first input 101 and thesecond input 102 of the resonant converter circuit 100, respectively,for receiving an input voltage V_(1n).

In this exemplary embodiment shown in FIGS. 1 and 2, the switch networkcircuit SNC₁/SNC₂ of each resonant converter G₁/G₂ comprises afull-bridge circuit. In another embodiment, the switch network circuitSNC₁/SNC₂ of each resonant converter G₁/G₂ comprises a half-bridgecircuit (not shown).

In one embodiment, each of the first and second output capacitors C_(F1)and C_(F2) includes one or more high frequency filtering capacitors.

In the embodiment shown in FIGS. 1 and 2, each of the first and secondrectifiers of each resonant converter comprises a half-bridge circuit.The half-bridge circuit is formed of, for example, two TDSON-8 packagedMOS transistors. In another embodiment, each rectifier includes afull-bridge circuit.

As such a configuration, the resonant converter circuit 100 operates inan interleaved mode. Ideally, the amplitudes of the output currents ofthe rectifiers in the two phases are equal, while and phases are shiftedat 90°, and thus an output current of the common output capacitor C₀ hassmall ripples or no ripples. However, in practice, the conductivewires/leads transmitting the rectifier outputs to the common outputcapacitor in the two-phase interleaved converters may have differentlengths and thus different parasitic resistances and parasiticinductances generated therein. The generated parasitic resistances andinductances may cause the asymmetry of the output currents, whichresults in the ripple increase of the output capacitor and deterioratesthe parallel-interleaved effect.

According to embodiments of the present invention, different layouts ofthe multiple transformers and the multiple rectifiers of the resonantconverter circuit are provided, in which the multiple transformers andthe multiple rectifiers of the multi-phase converters are interleavinglyarranged to be symmetrical to the common output polarized capacitor(s)so as to ensure the rectifier outputs of each phase relative to thecommon output polarized capacitor is symmetrical, thereby reducing theoutput ripples of the current of the output capacitors.

Referring now to FIG. 3, the layout 300 of the resonant convertercircuit 100 shown in FIG. 1 is illustrated according to one embodimentof the present invention. Specifically, the layout 300 includes a mainboard 360, a first sub-board 361 and a second sub-board 362 spaced-apartand vertically attached to the main board 360 along a direction 365 thatis determined based on a specific product design. In one embodiment,each of the main board 360, the first sub-board 361 and the secondsub-board 362 includes a printed circuit board (PCB).

In the layout 300, the first rectifiers R_(1,1) and R_(2,1) of the firstand second resonant converters G₁ and G₂ and the first output capacitorC_(F1) are spaced-apart disposed on one side of the first sub-board 361such that the first output capacitor C_(F1) is placed between the firstrectifiers R_(1,1) and R_(2,1) of the first and second resonantconverters G₁ and G₂. Preferably, the first rectifiers R_(1,1) andR_(2,1) of the first and second resonant converters G₁ and G₂ are placedsymmetrically on two lateral sides of the first output capacitor C_(F1).The first rectifiers R_(1,1) and R_(2,1) are electrically connected tothe first output capacitor C_(F1). Further, the first transformersT_(1,1) and T_(2,1) of the first and second resonant converters G₁ andG₂ are mounted on the other side of the first sub-board 361, spatiallyaligned with and electrically connected to the first rectifiers R_(1,1)and R_(2,1) of the first and second resonant converters G₁ and G₂,respectively. In the exemplary embodiment shown in FIG. 3, theconductive pins 331A and 331B of the secondary windings of the firsttransformer T_(1,1) of the first resonant converter G₁ is fixed on thefirst sub-board 361 by welding or other mounting means. Similarly, theconductive pins 341A and 341B of the secondary windings of the firsttransformer T_(2,1) of the second resonant converter G₂ is fixed on thefirst sub-board 361 by welding or other mounting means. Preferably, theconductive pins 331A and 331B, and 341A and 341B of the secondarywindings of the first transformers T_(1,1) and T_(2,1) of the first andsecond resonant converters G₁ and G₂, are symmetrically fixed on thefirst sub-board 361. The first sub-board 361 has a positive output port311 and a negative output port 312 electrically parallel-connected tothe first output capacitor C_(F1).

Furthermore, the second rectifiers R_(1,2) and R_(2,2) of the first andsecond resonant converters G₁ and G₂ and the second output capacitorC_(F2) are spaced-apart disposed on one side of the second sub-board 362such that the second output capacitor C_(F2) is placed between thesecond rectifiers R_(1,2) and R_(2,2) of the first and second resonantconverters G₁ and G₂. Preferably, the second rectifiers R_(1,2) andR_(2,2) of the first and second resonant converters G₁ and G₂ are placedsymmetrically on two lateral sides of the second output capacitorC_(F2). The second rectifiers R_(1,2) and R_(2,2) are electricallyconnected to the second output capacitor C_(F1). In addition, the secondtransformers T_(1,2) and T_(2,2) of the first and second resonantconverters G₁ and G₂ are mounted on the other side of the secondsub-board 362, spatially aligned with and electrically connected to thesecond rectifiers R_(1,2) and R_(2,2) of the first and second resonantconverters G₁ and G₂, respectively. In the exemplary embodiment shown inFIG. 3, the conductive pins 332A and 332B of the secondary windings ofthe second transformer T_(1,2) of the first resonant converter G₁ isfixed on the second sub-board 362 by welding or other mounting means.Similarly, the conductive pins 342A and 342B of the secondary windingsof the second transformer T_(2,2) of the second resonant converter G₂ isfixed on the second sub-board 362 by welding or other mounting means.Preferably, the conductive pins 332A and 332B, and 342A and 342B of thesecondary windings of the second transformers T_(1,2) and T_(2,2) of thefirst and second resonant converters G₁ and G₂, are symmetrically fixedon the first sub-board 361. The second sub-board 362 has a positiveoutput port 321 and a negative output port 322 electricallyparallel-connected to the second output capacitor C_(F2). The positiveoutput port 311 and the negative output port 312 of the first sub-board361 are eclectically connected to the positive output port 321 and thenegative output port 322 of the second sub-board 362, respectively,which in turn, are eclectically connected to the first and secondoutputs 103 and 104 of the resonant converter circuit.

By welding the positive output ports 311 and 321 and the negative outputports 312 and 322 of the first and second sub-boards 361 and 362 to themain board 360, the first sub-board 361 and the second sub-board 362 aresecured to the main board 360.

Additionally, the layout 300 may further comprises one or more polarizedcapacitors, e.g., C_(O1), C_(O2), C_(O3), disposed on the main board360, and are electrically parallel-connected to the first and secondoutputs 103 and 104 of the resonant converter circuit. The placements ofthe rectifiers R_(1,1), R_(1,2), R_(2,1) and R_(2,2) and thecorresponding transformers T_(1,1), T_(1,2), T_(2,1), and T_(2,2) arepreferably symmetrical to the one or more polarized capacitors.

FIG. 4 shows another embodiment of the layout of the resonant convertercircuit 100 shown in FIG. 1. In the embodiment, the layout 400 includesa main board 460, and a sub-board 461 vertically attached to the mainboard 460.

In this layout 400, the first rectifier R_(1,1) of the first resonantconverter G₁, the first output capacitor C_(F1), the first rectifierR_(2,1) of the second resonant converter G₂, the second rectifierR_(1,2) of the first resonant converter G₁, the second output capacitorC_(F2) and the second rectifier R_(2,2) of the second resonant converterG₂ are spaced-apart disposed in order on one side of the sub-board 461along a desired direction 465. Preferably, the first rectifier R_(1,1)of the first resonant converter G₁ and the first rectifier R_(2,1) ofthe second resonant converter G₂ are placed symmetrically to the firstoutput capacitor C_(F1). The second rectifier R_(1,2) of the firstresonant converter G₁ and the second rectifier R_(2,2) of the secondresonant converter G₂ are placed symmetrically to the second outputcapacitor C_(F2).

Furthermore, the first transformer T_(1,1) of the first resonantconverter G₁, the first transformer T_(2,1) of the second resonantconverter G₂, the second transformer T_(1,2) of the first resonantconverter G₁ and the second transformer T_(2,2) of the second resonantconverter G₂ are mounted in order on the other side of the sub-board461, spatially aligned with and electrically connected to the firstrectifier R_(1,1) of the first resonant converter G₁, the firstrectifier R_(2,1) of the second resonant converter G₂, the secondrectifier R_(1,2) of the first resonant converter G₁ and the secondrectifier R_(2,2) of the second resonant converter G₂, respectively. Inone embodiment, as shown in FIG. 4, each of the first transformerT_(1,1) of the first resonant converter G₁, the first transformerT_(2,1) of the second resonant converter G₂, the second transformerT_(1,2) of the first resonant converter G₁ and the second transformerT_(2,2) of the second resonant converter G₂ is fixed on the firstsub-board 461 by welding the conductive pins (431A, 431B)/(441A,441B)/(432A, 432B)/(442A, 442B) of the secondary windings of thecorresponding transformer T_(1,1)/T_(2,1)/T_(1,2)/T_(2,2) on thesub-board 461.

In addition, the sub-board 461 has a first positive output port 411 anda first negative output port 412 electrically parallel-connected to thefirst output capacitor C_(F1), and a second positive output port 421 anda second negative output port 422 electrically parallel-connected to thesecond output capacitor C_(F2). The first positive output port 412 andthe first negative output port 412 electrically parallel-connected tothe second positive output port 421 and the second negative output port422, which are in turn, electrically parallel-connected to the first andsecond outputs 103 and 104 of the resonant converter circuit. Similarly,by welding the first and second positive output ports 411 and 421 andthe first and second negative output ports 412 and 422 of the sub-boards461 to the main board 460, the sub-board 461 is secured to the mainboard 460.

In this exemplary embodiment shown in FIG. 4, three polarizedcapacitors, C_(O1), C_(O2) and C_(O3) are electricallyparallel-connected to the first and second outputs 103 and 104 of theresonant converter circuit. Similarly, the placements of the rectifiersR_(1,1), R_(1,2), R_(2,1) and R_(2,2) and the corresponding transformersT_(1,1), T_(1,2), T_(2,1), and T_(2,2) are preferably symmetrical to theone or more polarized capacitors.

Referring to FIGS. 5 and 6, a resonant converter circuit 500 is shownaccording to another embodiment of the present invention. In theexemplary embodiment, the resonant converter circuit 500 includes Mresonant converters, {G_(m)}, m=1, 2, 3, . . . , M, M being an integergreater than one.

As shown in FIG. 6, each resonant converter G_(m) has an resonant tank,N transformers {T_(m,n)}, and N rectifiers, {R_(m,n)}, n=1, 2, 3, . . .N, N being an integer greater than one. Each transformer T_(m,n)includes a primary winding and at least one secondary winding. Theresonant tank and the primary windings of the N transformers areelectrically connected to each other in series. Each rectifier R_(m,n)is electrically coupled to the at least one secondary winding of arespective transformer T_(m,n). In the embodiment shown in FIG. 6, eachrectifier R_(m,n) includes a half-bridge circuit formed of for example,two MOS switches. Additionally, a full-bridge circuit can also be usedas the rectifier R_(m,n). Each rectifier R_(m,n) has a first output anda second output.

As shown in FIG. 5, the multiple transformers {T_(m,n)} and the multiplerectifiers {R_(m,n)}, where m=1, 2, 3, . . . , M, and n=1, 2, 3, . . .N, are arranged in N groups, {B_(n)}. Each group B_(n) includes all then-th transformers T_(1,n), T_(2,n), T_(3,n), . . . T_(M,n) and the n-threctifiers R_(1,n), R_(2,n), R_(3,n), . . . R_(M,n) of the M resonantconverters {G_(m)}. For each group B_(n), the first and second outputsof the n-th rectifiers R_(1,n), R_(2,n), R_(3,n), . . . R_(M,n) of the Mresonant converters {G_(m)} are electrically parallel-connected to an-th output capacitor, C_(Fn), which is in turn, electrically connectedbetween the first and second outputs 103 and 104 of the resonantconverter circuit 500. Each output capacitor CF_(n) comprises one ormore high frequency filtering capacitors. In addition, one or morepolarized capacitor Co may electrically coupled between the first andsecond outputs 103 and 104 of the resonant converter circuit 500.

Further, each resonant converter G_(m) may also includes a switchnetwork circuit, NC_(m), electrically coupled to the resonant tank. Theswitch network circuit NC_(m) can be a half-bridge circuit or afull-bridge circuit.

Additionally, each resonant converter G_(m) has a first input and asecond input electrically coupled to the switch network circuit NC_(m).In the exemplary embodiment shown in FIG. 5, the second input of any onebut the last resonant converter G_(m) is electrically series-connectedto the first input of its immediate next resonant converter G_(m+1). Thefirst input of the first resonant converter G₁ and the second input ofthe last resonant converter G_(M) are electrically connected to thefirst input 101 and the second input 102 of the resonant convertercircuit 500, respectively, for receiving an input voltage V_(in).

FIG. 7 shows schematically a resonant converter circuit 700 according toyet another embodiment of the present invention. Similar to the resonantconverter circuit 500 shown in FIGS. 5 and 6, the resonant convertercircuit 700 includes M resonant converters, {G_(m)}, m=1, 2, 3, . . . M,M being an integer greater than one. Except that each resonant converterG_(m) includes only N transformers {T_(m,n)}, and N rectifiers,{R_(m,n)}, n=1, 2, 3, . . . N, N being an integer greater than one. Eachtransformer T_(m,n) includes a primary winding and a secondary winding.The primary windings of the N transformers of each resonant converterG_(m) are electrically connected to each other in series. Each rectifierR_(m,n) is electrically coupled to the secondary winding of a respectivetransformer T_(m,n). Each rectifier R_(m,n) has a first output and asecond output.

As shown in FIG. 7, the multiple transformers {T_(m,n)} and the multiplerectifiers {R_(m,n)}, where m=1, 2, 3, . . . M, and n=1, 2, 3, . . . N,are arranged in N groups, {B_(n)}. Each group B_(n) includes all then-th transformers T_(1,n), T_(2,n), T_(3,n), . . . T_(M,n) and the n-threctifiers R_(1,n), R_(2,n), R_(3,n), . . . R_(M,n) of the M resonantconverters {G_(m)}. For each group B_(n), the first and second outputsof the n-th rectifiers R_(1,n), R_(2,n), R_(3,n), . . . R_(M,n) of the Mresonant converters {G_(m)} are electrically parallel-connected to an-th output capacitor, C_(Fn), which is in turn, electrically connectedbetween the first and second outputs 103 and 104 of the resonantconverter circuit 700. Each output capacitor CF_(n) comprises one ormore high frequency filtering capacitors. In addition, one or morepolarized capacitor Co may electrically coupled between the first andsecond outputs 103 and 104 of the resonant converter circuit 700.

Further, each resonant converter G_(m) may also includes a switchnetwork circuit, NC_(m), electrically coupled to the N transformers{T_(m,n)}.

Additionally, each resonant converter G_(m) has a first input and asecond input electrically coupled to the switch network circuit NC_(m).In the exemplary embodiment shown in FIG. 7, the second input of any onebut the last resonant converter G_(m) is electrically series-connectedto the first input of its immediate next resonant converter G_(m+1). Thefirst input of the first resonant converter G₁ and the second input ofthe last resonant converter G_(M) are electrically connected to thefirst input 101 and the second input 102 of the resonant convertercircuit 700, respectively, for receiving an input voltage V_(in).

In one aspect of the present invention, a layout of the resonantconverter circuit 500/700 is provided. The layout (not shown) includes amain board, and N sub-boards spaced-apart and vertically attached to themain board along a direction defined by a production design. In thelayout, for each group B_(n), the n-th rectifiers R_(1,n), R_(2,n),R_(3,n), . . . R_(M,n) of the M resonant converters {G_(m)} and the n-thoutput capacitor C_(Fn) are spaced-apart disposed on one side of then-th sub-board, while the n-th transformers T_(1,n), T_(2,n), T_(3,n), .. . T_(M,n) of the M resonant converters {G_(m)} are mounted on theother side of the n-th sub-board, spatially aligned with andelectrically connected to the n-th rectifiers R_(1,n), R_(2,n), R_(3,n),. . . R_(M,n) of the M resonant converters {G_(m)}, respectively. In oneembodiment, the n-th transformers T_(1,n), T_(2,n), T_(3,n), . . .T_(M,n) of the M resonant converters {G_(m)} are mounted on the otherside of the first sub-board by fixing pins of the secondary windings ofeach of the n-th transformers T_(1,n), T_(2,n), T_(3,n), . . . T_(M,n)of the M resonant converters {G_(m)} on the n-th sub-board. Preferably,the n-th rectifiers R_(1,n), R_(2,n), R_(3,n), . . . R_(M,n) of the Mresonant converters {G_(m)} are placed symmetrically on two sides of then-th output capacitor on the n-th sub-board.

In one embodiment, the n-th sub-board has a positive output port and anegative output port electrically parallel-connected to the respectiven-th output capacitor. The positive and negative output ports of the Nsub-boards are electrically parallel-connected to the first and secondoutputs of the resonant converter circuit, respectively.

The layout further has one or more polarized capacitors disposed on themain board, and are electrically parallel-connected to the first andsecond outputs of the resonant converter circuit 500/700.

According to the present invention, another embodiment of the layout ofthe resonant converter circuit 500/700 is also provided. The layout (notshown) includes a main board, and a sub-board vertically attached to themain board. In the layout, for each group B_(n), the n-th rectifiersR_(1,n), R_(2,n), R_(3,n), . . . R_(M,n) of the M resonant converters{G_(m)} and the n-th output capacitor C_(Fn) are spaced-apart andorderly disposed on one side of the sub-board along a predetermineddirection, while the n-th transformers T_(1,n), T_(2,n), T_(3,n), . . .T_(M,n) of the M resonant converters {G_(m)} are mounted on the otherside of the sub-board along the predetermined direction, spatiallyaligned with and electrically connected to the n-th rectifiers R_(1,n),R_(2,n), R_(3,n), . . . R_(M,n) of the M resonant converters {G_(m)},respectively, so as to define a respective sub-layout. Each sub-layoutis arranged along the predetermined direction.

Preferably, the n-th rectifiers R_(1,n), R_(2,n), R_(3,n), . . . R_(M,n)of the M resonant converters {G_(m)} are placed symmetrically on twosides of the n-th output capacitor on the sub-board.

In one embodiment, the n-th transformers T_(1,n), T_(2,n), T_(3,n), . .. T_(M,n) of the M resonant converters {G_(m)} are mounted on the otherside of the first sub-board by fixing pins of the secondary windings ofeach of the n-th transformers T_(1,n), T_(2,n), T_(3,n), . . . T_(M,n)of the M resonant converters {G_(m)} symmetrically on the sub-board.

In one embodiment, the sub-board has M pairs of positive and negativeoutput ports. Each pair of the positive and negative output ports iselectrically parallel-connected to the respective output capacitor. TheM pairs of positive and negative output ports are electricallyparallel-connected to the first and second outputs of the resonantconverter circuit, respectively.

In sum, the present invention, among other things, recites multi-phaseparallel-interleaved converter circuits with each phase having two ormore transformers and two or more rectifiers electrically coupled to thetwo or more transformers, and layouts of the multiple transformers andthe multiple rectifiers of the multi-phase parallel-interleavedconverter circuits. In the layouts, the multiple transformers and themultiple rectifiers of the multi-phase converters are interleavinglyarranged to be symmetrical to the common output polarized capacitor(s)so as to ensure the rectifier outputs of each phase relative to thecommon output polarized capacitor is symmetrical, thereby reducing theoutput ripples of the current of the output capacitors.

The foregoing description of the exemplary embodiments of the inventionhas been presented only for the purposes of illustration and descriptionand is not intended to be exhaustive or to limit the invention to theprecise forms disclosed. Many modifications and variations are possiblein light of the above teaching.

The embodiments were chosen and described in order to explain theprinciples of the invention and their practical application so as toactivate others skilled in the art to utilize the invention and variousembodiments and with various modifications as are suited to theparticular use contemplated. Alternative embodiments will becomeapparent to those skilled in the art to which the present inventionpertains without departing from its spirit and scope. Accordingly, thescope of the present invention is defined by the appended claims ratherthan the foregoing description and the exemplary embodiments describedtherein.

1. A converter circuit having a first output and a second output,comprising: a first converter and a second converter, each convertercomprising: (a) a switch network circuit; (b) a first transformer and asecond transformer, each transformer having a primary winding and atleast one secondary winding, wherein the switch network circuit and theprimary windings of the first and second transformers are electricallyconnected to each other; and (c) a first rectifier and a secondrectifier electrically coupled to the secondary windings of the firsttransformer and the second transformer, respectively, each rectifierhaving a first output and a second output, wherein the first and secondoutputs of the first rectifiers of the first and second converters areelectrically parallel-connected to a first output capacitor that iselectrically connected between the first and second outputs of theconverter circuit; and wherein the first and second outputs of thesecond rectifiers of the first and second converters are electricallyparallel-connected to a second output capacitor that is electricallyconnected between the first and second outputs of the converter circuit.2. The converter circuit of claim 1, wherein one of the converters is aresonant converter.
 3. The converter circuit of claim 1, wherein one ofthe converters is a PWM converter.
 4. The resonant converter circuit ofclaim 2, wherein each resonant converter has a first input and a secondinput, wherein the second input of the first resonant converter iselectrically series-connected to the first input of the second resonantconverter, and wherein the first input of the first resonant converterand the second input of the second resonant converter are electricallycoupled to a voltage source for receiving an input voltage.
 5. Theresonant converter circuit of claim 4, wherein each resonant convertercomprises a resonant tank, electrically coupled between switch networkcircuit and the transformer.
 6. The resonant converter circuit of claim5, wherein each switch network circuit electrically coupled between thefirst and second inputs and the resonant tank.
 7. The resonant convertercircuit of claim 6, wherein the switch network circuit of each resonantconverter comprises a half-bridge circuit or a full-bridge circuit. 8.The resonant converter circuit of claim 2, wherein each of the first andsecond output capacitors comprises one or more high frequency filteringcapacitors.
 9. The resonant converter circuit of claim 2, wherein eachof the first and second rectifiers of each resonant converter comprisesa half-bridge circuit or a full-bridge circuit.
 10. A layout of theconverter circuit of claim 1, comprising: a main board, a firstsub-board and a second sub-board spaced-apart and vertically attached tothe main board along a predetermined direction, wherein the firstrectifiers of the first and second converters and the first outputcapacitor are spaced-apart disposed on one side of the first sub-boardsuch that the first output capacitor is placed between the firstrectifiers of the first and second converters, and wherein the firsttransformers of the first and second converters are mounted on the otherside of the first sub-board, spatially aligned with and electricallyconnected to the first rectifiers of the first and second converters,respectively; and wherein the second rectifiers of the first and secondconverters and the second output capacitor are spaced-apart disposed onone side of the second sub-board such that the second output capacitoris placed between the second rectifiers of the first and secondconverters, and wherein the second transformers of the first and secondconverters are mounted on the other side of the second sub-board,spatially aligned with and electrically connected to the secondrectifiers of the first and second converters, respectively.
 11. Thelayout of the converter circuit of claim 10, wherein the firstrectifiers of the first and second converters are placed symmetricallyon two sides of the first output capacitor, and wherein the secondrectifiers of the first and second converters are placed symmetricallyon two sides of the second output capacitor.
 12. The layout of theconverter circuit of claim 10, wherein the first transformers of thefirst and second converters are mounted on the other side of the firstsub-board by fixing pins of the secondary windings of the firsttransformers of the first and second converters symmetrically on thefirst sub-board, and wherein the second transformers of the first andsecond converters are mounted on the other side of the second sub-boardby symmetrically fixing pins of the secondary windings of the secondtransformers of the first and second converters symmetrically on thesecond sub-board.
 13. The layout of the converter circuit of claim 10,wherein each sub-board has a positive output port and a negative outputport electrically parallel-connected to a respective one of the firstand second output capacitors, and wherein the positive and negativeoutput ports of the first sub-board are electrically parallel-connectedto the positive and negative output ports of the second sub-board,respectively, which are electrically parallel-connected to the first andsecond outputs of the converter circuit.
 14. The layout of the convertercircuit of claim 13, further comprising one or more polarized capacitorsdisposed on the main board, and wherein the one or more polarizedcapacitors are electrically parallel-connected to the first and secondoutputs of the converter circuit.
 15. A layout of the converter circuitof claim 1, comprising: a main board, and a sub-board verticallyattached to the main board, wherein the first rectifier of the firstconverter, the first output capacitor, the first rectifier of the secondconverter, the second rectifier of the first converter, the secondoutput capacitor and the second rectifier of the second converter arespaced-apart and orderly disposed on one side of the sub-board along apredetermined direction such that the first output capacitor is placedbetween the first rectifier of the first converter and the firstrectifier of the second converter, and the second output capacitor isplaced between the second rectifier of the first converter and thesecond rectifier of the second converter; and wherein the firsttransformer of the first converter, the first transformer of the secondconverter, the second transformer of the first converter and the secondtransformer of the second converter are orderly mounted on the otherside of the sub-board, spatially aligned with and electrically connectedto the first rectifier of the first converter, the first rectifier ofthe second converter, the second rectifier of the first converter andthe second rectifier of the second converter, respectively.
 16. Thelayout of the converter circuit of claim 15, wherein the firsttransformer of the first converter, the first transformer of the secondconverter, the second transformer of the first converter and the secondtransformer of the second converter are orderly mounted on the otherside of the first sub-board by fixing pins of the secondary windings ofthe corresponding transformers on the sub-board.
 17. The layout of theconverter circuit of claim 15, wherein the sub-board has a firstpositive output port and a first negative output port electricallyparallel-connected to the first output capacitor, and a second positiveoutput port and a second negative output port electricallyparallel-connected to the second output capacitor, and wherein the firstpositive output port and the first negative output port electricallyparallel-connected to the second positive output port and the secondnegative output port, which are electrically parallel-connected to thefirst and second outputs of the converter circuit.
 18. The layout of theconverter circuit of claim 17, further comprising one or more polarizedcapacitors disposed on the main board, and wherein the one or morepolarized capacitors are electrically parallel-connected to the firstand second outputs of the converter circuit.
 19. The layout of theconverter circuit of claim 15, wherein the converter is resonantconverter.
 20. A resonant converter circuit having a first output and asecond output, comprising: M resonant converters, {G_(m)}, m=1, 2, 3, .. . , M, M being an integer greater than one, each resonant converterG_(m) comprising: (a) N transformers {T_(m,n)}, n=1, 2, 3, . . . N, Nbeing an integer greater than one, each transformer T_(m,n) having aprimary winding and at least one secondary winding, wherein the primarywindings of the N transformers are electrically connected to each otherin series; and (b) N rectifiers, {R_(m,n)}, each rectifier R_(m,n)having a first output and a second output, and electrically coupled tothe at least one secondary winding of a respective transformer T_(m,n),wherein the transformers {T_(m,n)} and the rectifiers {R_(m,n)} of the Mresonant converters {G_(m)} are arranged in N groups such that eachgroup includes the n-th transformers T_(1,n), T_(2,n), T_(3,n), . . .T_(M,n) and the n-th rectifiers R_(1,n), R_(2,n), R_(3,n), . . . R_(M,n)of the M resonant converters {G_(m)}, wherein for each group, the firstand second outputs of the n-th rectifiers R_(1,n), R_(2,n), R_(3,n), . .. R_(M,n) of the M resonant converters {G_(m)} are electricallyparallel-connected to a n-th output capacitor, C_(Fn), which iselectrically connected between the first and second outputs of theresonant converter circuit.
 21. The resonant converter circuit of claim20, wherein each resonant converter G_(m) has a first input and a secondinput, wherein the second input of any one but the last resonantconverter G_(m) is electrically series-connected to the first input ofits immediate next resonant converter G_(m+1), and wherein the firstinput of the first resonant converter G₁ and the second input of thelast resonant converter G_(M) are electrically coupled to a voltagesource for receiving an input voltage.
 22. The resonant convertercircuit of claim 20, wherein each resonant converter G_(m) furthercomprises an resonant tank, wherein the resonant tank and the primarywindings of the N transformers are electrically connected to each otherin series
 23. The resonant converter circuit of claim 20, wherein eachresonant converter G_(m) further comprises a switch network circuit,NC_(m), electrically coupled between the first and second inputs and theresonant tank.
 24. The resonant converter circuit of claim 21, whereinthe switch network circuit NC_(m) of each resonant converter G_(m)comprises a half-bridge circuit or a full-bridge circuit.
 25. Theresonant converter circuit of claim 20, wherein each output capacitorC_(Fn) comprises one or more high frequency filtering capacitors. 26.The resonant converter circuit of claim 20, wherein each rectifierR_(m,n) of each resonant converter G_(m) comprises a half-bridge circuitor a full-bridge circuit.
 27. A layout of the resonant converter circuitof claim 20, comprising: a main board, and N sub-boards spaced-apart andvertically attached to the main board along a predetermined direction,wherein for each group, the n-th rectifiers R_(1,n), R_(2,n), R_(3,n), .. . R_(M,n) of the M resonant converters {G_(m)} and the n-th outputcapacitor C_(Fn) are spaced-apart disposed on one side of the n-thsub-board, and the n-th transformers T_(1,n), T_(2,n), T_(3,n), . . .T_(M,n) of the M resonant converters {G_(m)} are mounted on the otherside of the n-th sub-board, spatially aligned with and electricallyconnected to the n-th rectifiers R_(1,n), R_(2,n), R_(3,n), . . .R_(M,n) of the M resonant converters {G_(m)}, respectively.
 28. Thelayout of the resonant converter circuit of claim 27, wherein the n-threctifiers R_(1,n), R_(2,n), R_(3,n), . . . R_(M,n) of the M resonantconverters {G_(m)} are placed symmetrically on two sides of the n-thoutput capacitor on the n-th sub-board.
 29. The layout of the resonantconverter circuit of claim 27, wherein the n-th transformers T_(1,n),T_(2,n), T_(3,n), . . . T_(M,n) of the M resonant converters {G_(m)} aremounted on the other side of the first sub-board by fixing pins of thesecondary windings of each of the n-th transformers T_(1,n), T_(2,n),T_(3,n), . . . T_(M,n) of the M resonant converters {G_(m)}symmetrically on the n-th sub-board.
 30. The layout of the resonantconverter circuit of claim 27, wherein the n-th sub-board has a positiveoutput port and a negative output port electrically parallel-connectedto the respective n-th output capacitor.
 31. The layout of the resonantconverter circuit of claim 30, wherein the positive and negative outputports of the N sub-boards are electrically parallel-connected to thefirst and second outputs of the resonant converter circuit,respectively.
 32. The layout of the resonant converter circuit of claim31, further comprising one or more polarized capacitors disposed on themain board, and wherein the one or more polarized capacitors areelectrically parallel-connected to the first and second outputs of theresonant converter circuit.
 33. A layout of the resonant convertercircuit of claim 20, comprising: a main board, and a sub-boardvertically attached to the main board, wherein for each group, the n-threctifiers R_(1,n), R_(2,n), R_(3,n), . . . R_(M,n) of the M resonantconverters {G_(m)} and the n-th output capacitor CF_(n) are spaced-apartand orderly disposed on one side of the sub-board along a predetermineddirection, and the n-th transformers T_(1,n), T_(2,n), T_(3,n), . . .T_(M,n) of the M resonant converters {G_(m)} are mounted on the otherside of the sub-board along the predetermined direction, spatiallyaligned with and electrically connected to the n-th rectifiers R_(1,n),R_(2,n), R_(3,n), . . . R_(M,n) of the M resonant converters {G_(m)},respectively, so as to define a respective sub-layout; and wherein eachsub-layout is arranged along the predetermined direction.
 34. The layoutof the resonant converter circuit of claim 33, wherein the n-threctifiers R_(1,n), R_(2,n), R_(3,n), . . . R_(M,n) of the M resonantconverters {G_(m)} are placed symmetrically on two sides of the n-thoutput capacitor on the sub-board.
 35. The layout of the resonantconverter circuit of claim 33, wherein the n-th transformers T_(1,n),T_(2,n), T_(3,n), . . . T_(M,n) of the M resonant converters {G_(m)} aremounted on the other side of the first sub-board by fixing pins of thesecondary windings of each of the n-th transformers T_(1,n), T_(2,n),T_(3,n), . . . T_(M,n) of the M resonant converters {G_(m)}symmetrically on the sub-board.
 36. The layout of the resonant convertercircuit of claim 33, wherein the sub-board has M pairs of positive andnegative output ports, each pair of the positive and negative outputports electrically parallel-connected to the respective outputcapacitor, and wherein the M pairs of positive and negative output portsare electrically parallel-connected to the first and second outputs ofthe resonant converter circuit, respectively.
 37. The layout of theresonant converter circuit of claim 36, further comprising one or morepolarized capacitors disposed on the main board, and wherein the one ormore polarized capacitors are electrically parallel-connected to thefirst and second outputs of the resonant converter circuit.